PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Eastern Cooperative Oncology Group (ECOG) 0-3 Life expectancy: More than 8 weeks Hematopoietic: Absolute neutrophil count at least 1,000/mm^3 Hepatic: aspartate aminotransferase (AST) or alanine transaminase (ALT) no greater than 2 times upper limit of normal (ULN) Bilirubin no greater than 2 mg/dL Renal: Creatinine no greater than 1.5 times ULN Calcium no greater than 12 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception Capable of swallowing intact study medication tablets No concurrent serious infection No grade 3 or greater peripheral neuropathy No life-threatening illness unrelated to tumor No other active or invasive cancer within the past 3 years except nonmelanoma skin cancer